TECHNICAL FEATURE
drain TRADER
Clay Drainage: digging deeper into Brownfield Sites
Brownfield sites are becoming an increasingly popular option for new-build residential and commercial developments. However, as the land can be contaminated fromprevious industrial use and possible chemical exposure, there are a number of considerations contractors and engineers must address to ensure drainage solutions remain viable. Here, Joana Januseviciute, productmanager for clayware at Hepworth Clay, discusses howtried-and-tested clay drainage is an ideal solution.
The latest on brownfield sites
There are currently over 66,000 hectares of possible brownfield sites in England alone, with around a third of these located in Greater London, the South East and the East.With the introduction of Brownfield Land Registers setting out clear, up to date information and cases of planning permission for housing and commercial developments across the UK, it’s predicted that development on brownfield siteswill rise considerably over the coming years. Thiswill go someway to alleviating the current housing crisis. Land Remediation Tax Relief,which allows developers to claimrelief of 150 per cent for costs incurred cleaning up contaminated land, also serves as an attractive incentive to build on brownfield land.
As brownfield sites are known to be lowcost when it comes to purchasing the land, builders and investors are particularly interested in redeveloping these sites. In comparison to greenfield sites, they also typically become availablemuch quicker,making the process
frombuying to developingmuch faster. However, they can have potential contamination fromtheir previous use, often fromindustrialwaste and pollution, and in some cases exposure to harsh chemicals. This means residential and commercial repurposing can become a challenge in several areas, particularlywhen it comes to below-ground drainage.
That’swhy it’s important for contractors to thoroughly assess the land in question,which includes surveys on the soil. Once the survey is completed, a course of action can be decided on, as itwill then be known if it’s possible to remove all the contaminants fromthe ground. However, if this is not feasible, an appropriate below-ground pipe systemthat’s able to withstand the leftover contaminants and chemicals can be specified accordingly. Clay has the ability to copewithmost residual contaminants, oftenmaking it the ideal choice, although contractors can seek guidance from themanufacturer of the pipe systemin regards to suitability for their specific project.
If there is residual contamination, it’s also important that contractors specify the correct coupling, such as the nitrile seals used in Hepworth Clay products. The nitrile sealing ring is capable of resisting contamination involving oil and petrol type (hydrocarbon) contamination,which is a concern found on many brownfield redevelopment sites, especially if the landwas previously used for military or industrial purposes. By knowing the seal is just as strong as the pipe, developers can rest assured knowing their pipe systems
46 drain TRADER | October 2020 |
www.draintraderltd.com arewater-tight.
Why clay piping? Due to its inert nature and 100 per cent natural make up, the clay pipes are impervious and resistant to practically all chemicals and compounds thatmay be found in the ground, with the exception of hydrofluoric acid (HF). Boasting an average lifespan ofmore than 100 years, it’s also a remarkably reliable and durable solution. This longevity is due to the material characteristics and strength of vitrified clay pipe and fittings,which does not change after the installation process. Clay pipes are also capable ofwithstandingmost
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